White Box Testing

Testing based on an analysis of internal workings and structure of a piece of software. Also known as Structural Testing / Glass Box Testing / Clear. Tests are based on coverage of code statements, branches, paths, conditions.

Aims to establish that the code works as designed Examines the internal structure and implementation of the program .
Target specific paths through the programNeeds accurate knowledge of the design,
implementation and code.

Statement coverage

Branch coverage

Condition coverage

Path coverage

Data flow-based testing

Mutation testing


Design test cases so that every statement in a program is executed at least once. Unless a statement is executed, we have no way of knowing if an error exists in that statement Example:

Euclid's GCD computation algorithm:

By choosing the test set {(x=3, y=3), (x=4, y=3), (x=3, y=4)} all statements are executed at east once.

int f1(int x, int y){
while (x != y){
if (x>y) then
x=x-y;
else y=y-x;
}
return x; }


Test cases which exercise basic set will execute every statement at least once. Aim is to derive a logical complexity measure of a procedural design and use this as a guide for defining a basic set of execution paths.

Flow Graph Notation

On a flow graph:

Arrows called edges represent flow of control

Circles called nodes represent one or more actions

Areas bounded by edges and regions called regions

A predicate node is a node containing a condition

Any procedural design can be translated into a flow graph. Note that compound Boolean expressions at tests generate at least two predicate nodes and additional arcs.

29.2
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